1. Please take 30 seconds to register your free account to remove most ads, post topics, make friends, earn reward points at our store, and more!  
     
    TalkBass.com has been uniting the low end since 1998.  Join us! :)

HELP!!! GK Backline 600 problem

Discussion in 'Amps and Cabs [BG]' started by martarmetal, Jul 22, 2012.


  1. OK, so unfortunately I had to sell my 1001RB and replace it with a used Backline 600. I install it in my rack, use the patch-bay to send signal to my BBE sonic Maximizer and then return it to the amp. I also use the "tuner" jack to send signal to my rack-mount tuner...Only problem is the volume is so low, I cranked it all to "11" and and it still seemed like a small 10 watt toy amp. Im not being over dramatic either. I also noticed that the tuner wasn't picking up any signal. So I unplugged everything from the patch-bay and the amp WOKE UP. Now were using 300 watts, but now I cant use my Sonic Maximizer or tuner... Clearly theres a problem with the patch bay on the amp but has anyone ever encountered this before??? Possible repair ideas??? ANY ideas??? Dont worry...If anyone was wondering...I DO know how to use the patch-bay properly. Thank you in advance :)
     
  2. maybe try cleaning the jacks real good with some De-Oxit contact cleaner
     
  3. Thank you!! I will try that tomorrow. Should I disassemble the amp and remove the jacks to clean them or just spray a little cleaner in the jacks? I dont want to mess up any other electronics in to process of repairing the FX loop.
     
  4. no need to disassemble, you can spray some in the jacks - but, put some on a plug and plug it in and out of each jack and few times
     
  5. Will do. Hopefully this works, but for $70 I cant really complain as long as it powers my cabs and doesn't sound like garbage.
     
  6. btw, did the amp ever work ok with the Maximizer, etc plugged in - in other words, was everything working ok and it just recently stopped? Or is this a new thing your trying and can’t get it to work? And good luck with the cleaner - I hope that does the trick for you.
     
  7. I just picked up this amp tonight and it hasnt worked with the maximizer or tuner since i pluged it in. All my equipment worked fine with the 1001RB amp so I know my gear is good. The Backline 600 was used and a little abused so im sure its an amp issue. It works fine when Im not using anything in the FX loop but as soon as anything gets plugged into the loop the amp craps out.
     
  8. ok. yeah, my guess is it’s dirty jacks and cleaning the jacks should fix the problem
     
  9. I think an easy way to find out if the issue is with the effects loop is to connect the effects loop with an effects pedal for testing or just patch the effects "sends" with the effects "return" with a cable to see if you come up with the same problem.
     
  10. I just did a test with my GK 400RB-III by patching the "send" with the "return" using an instrument cable. It works. Volume levels were the same with and without the patch.
     
  11. I patched the send directly to the return and still not dice, im on my way to get some contact cleaner
     
  12. Joe Nerve

    Joe Nerve Supporting Member

    Oct 7, 2000
    New York City
    Endorsing artist: Musicman basses
    A little off topic here, but curious.... I had a 1001RB that was part of a discontinued neo 212 combo that I think I was the only person on the planet to ever own. I also had an extra neo 2X12 cab, and a backline for a backup head. I wound up using the backline and the 212s and thought it sounded way better than the 1001RB. I could only push the 212s so far before they'd start breaking up, and the backline alone had more than enough power to do that. I sold the 212 combo, never missed the 1001 head, and like the backline waay more, for a variety of reasons. Curious on your take of the 2 heads, aside from the problem you're experiencing. What's your comparison of the 2?
     
  13. Well, Clearly there was boatloads more headroom with the 1001RB but that wasnt necessary for my uses and most people probably dont need that much power anyway. They both seem to be built like a tank. As far am my tone differences... Ive only had the Backline 600 for a day but I put in my $.02. The 1001rb seemed a little "crispier" that the BL600. Both have that unique GK growl but it seems like the BL600 had a little deeper growl, not muffled in any way, just deeper. Ill be sure to give a better opinion once I get a few more hours on the BL600.
     
  14. OK, so I got some DeOxit and followed the directions to apply it. Initially the amp crackled pretty bad and cut in and out while playing without use of the FX loop but it seems to be working alright now. However there are still problems with the FX loop. The "tuner" jack still does not work and when I plug a cable into the "return" jack the amp cuts out completely...BUT if I use the "send" jack and run it to my tuner i get signal to my tuner. This leads me to believe that the "return" and "tuner" jacks are faulty. I will apply more DeOxit to those jacks in hopes of resolving the problem but if that does not work are there any other suggestions? Im not sure if just the FX loop wiring is bad or could it be the entire amp circuitry going bad? The amp is absolutely usable but I would like to have the FX loop available for use as well.
     
  15. ok, so i took the amp apart to see it there was loose or broken wires, after i took the cover off i noticed there was more dust and dirt than should be inside an amp so.. i cleaned everything carefully, Nothing seemed wrong with wires or connections so after cleaning i gave it a test run. The "tuner" jack now works properly, YAYY!! and when i plug a cable into the "send" jack there is no malfunction BUT... The Return jack is still giving me problems, when the is a cable in the return jack the volume falls dramatically, at least 80% and the signal is super distorted. Does this sound like a faulty jack? If so is that a cheap fix at an amp tech or could it still be something else. Thank you to all who gave input and advice, it was very helpful!!
     
  16. Yes it could be a bad jack or bad solder joint to the jack. Not expensive to replace at all. So you understand how that jack functions: There is a second set of contacts inside the jack to pass the signal from the preamp to the power amp. If you insert a plug into the jack the contact is broken and the power amp input comes from the tip connection of the jack. Unused the internal connection can corrode (called fretting) as the signal is very low voltage and low current.
     
  17. jHawk Customs

    jHawk Customs

    Jun 25, 2012
    Mesa, AZ
    Authorized Builder - greenboy designs
    Does adjusting the "Boost" change the sound at all?
     
  18. Thank you B-string, when i cracked open the amp i found a fair amount of dirt and grime, more than DeOxit could handle even with a q-tip so im pretty sure the jack is corroded internally. Im not too savvy on soldering circuitry even though it seems easy enough so i think i will take it to a local amp tech to get the jack replaced. jHawk Customs, the Boost doesn't necessarily "change" the sound. It makes it louder, almost like a gain knob would do but without as much overdriven distortion, if anything i feel that the boost knob draws out out the lower frequencies and gives the bottom end a nice growl. Just use it sparingly because it can muddy your sound rather quickly.
     
  19. Its an easy repair for a tech. If you are not real good with working PCB's then you are making the right choice :). The Boost adds harmonic content it is not an overdrive distortion circuit :D
     
  20. jHawk Customs

    jHawk Customs

    Jun 25, 2012
    Mesa, AZ
    Authorized Builder - greenboy designs
    I was asking about the Boost since it is pre effect send.

    I have also seen single pedals in a chain have issues and drag the entire loop down.

    Seems more like corrosion though since you have trouble with the tuner jack as well.

    Hope it's an easy fix.
     

Share This Page